As the number of devices connected to data networks increase and higher data rates are required, there is a growing need for new transmission technologies enabling higher transmission rates over existing copper cabling infrastructures. Various efforts exist in this regard, including technologies that enable transmission rates that may even exceed Gigabits-per-second (Gbps) data rates over existing cabling. For example, the IEEE 802.3 standard defines the (Medium Access Control) MAC interface and physical layer (PHY) for Ethernet connections at 10 Mbps, 100 Mbps, 1 Gbps, and 10 Gbps data rates over twisted-pair copper cabling 100 m in length. With each 10× rate increase more sophisticated signal processing is required to maintain the 100 m standard cable range. However, connections longer than 100 m may require either the use of fiber or the placement of Ethernet switches, hubs, and/or repeaters, at mid-points in the connection to keep all cables less than 100 m in length.
Other efforts include the development of a standard for 10 Gigabits-per-second (Gbps) Ethernet transmission over twisted-pair cabling (10 GBASE-T). The emerging 10 GBASE-T PHY specification is intended to enable 10 Gbps connections over twisted-pair cabling at distances of up to 182 feet for existing cabling, and at distances of up to 330 feet for new cabling, for example. To achieve full-duplex transmission at 10 Gbps over four-pair twisted-pair copper cabling, elaborate digital signal processing techniques are needed to remove or reduce the effects of severe frequency-dependent signal attenuation, signal reflections, near-end and far-end crosstalk between the four pairs, and external signals coupled into the four pairs either from adjacent transmission links or other external noise sources. Moreover, new cabling specifications are being developed to diminish susceptibility to external electro-magnetic interferences.
Extending the range or distance at which standard based Ethernet PHY devices may operate with minimal changes to the PHY transceiver architectures that support, for example, 1 Gbps or 10 Gbps data rates, may enable new Ethernet PHY devices to be used and deployed in the broadband access market and possibly in new residential and enterprise applications. Moreover, features may be provided that may enable a single PHY device to operate in either a standard or an extended range mode of operation.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.